Energetic Complexes Research Articles

Six new complexes constructed from silver(I) and 2-(dinitromethylene)-1,3-diazacyclopentane (DNDZ): Synthesis, crystal structure and properties

Six different energetic silver complexes of 2-(dinitromethylene)-1,3-diazacyclopentane (DNDZ), Ag(DNDZ) (1), [Ag2(H2O)(DNDZ)]n (2), Ag(NH3)DNDZ (3), Ag(CH3NH2)(DNDZ) (4), Ag(C2H5NH2)(DNDZ) (5) and Ag(C3H7NH2)(DNDZ) (6), were first synthesized and structurally characterized. Complexes 2, 3, 5 and 6 were characterized by the single crystal X-ray diffraction analysis. Complexes 2, 5 and 6 crystallize in the monoclinic crystal system with space group P21/n containing four molecules per unit cell, but the crystal of complex 3 is triclinic with space group P-1 containing two molecules in each unit cell. Complexes 2 and 3 possess Ag⋯Ag interaction and corresponding central symmetric structure, but complexes 5 and 6 do not. Thermal behaviors of complexes 1-6 were determined and analyzed. The order of thermal stability for the six complexes is 4 > 3 >1 > 2 >5 > 6. Impact sensitivities for complexes 1-6 are >12 J, > 4 J, > 13 J, > 16 J, > 8 J and >7 J respectively, which corresponds well to the results of thermal stability for the six complexes except for complex 2. Moreover, natural bond orbital (NBO) analysis was used to investigate the bonding and hybridization of complex 3.

Highly functional energetic complexes: stability tuning through coordination diversity of isomeric propyl-linked ditetrazoles

A series of functional new energetic coordination compounds (ECCs) were prepared and their physicochemical properties tuned by the use of various metal(ii) centers and three different ditetrazolylpropane isomers.

Synthesis, Crystal Structure, and Properties of Energetic Complex Magnesium 5,5′‐Dinitramino‐3,3′‐bi[1,2,4‐triazolate] Hexahydrate

Alkaline Earth metal (Mg) energetic complex with 5,5′‐dinitramino‐3,3′‐bi[1,2,4‐triazolate] dihydrate (DNABT) has been synthesized and structurally characterized by FTIR spectroscopy, elemental analysis, and single X‐ray diffraction. The thermal decomposition processes of the complex and DNABT were studied by means of the TDA‐TG technologies. Sensitivity tests reveal that the complex is more insensitive to mechanical stimuli than DNABT. Combustion behavior shows that 1 has good color performances.

Four new energetic complexes constructed from nickel(II) and 2-(dinitromethylene)-1,3-diazacyclopentane: synthesis, characterization and thermal properties

Four new energetic nickel complexes of DNDZ [DNDZ = 2-(dinitromethylene)-1,3-diazacyclopentane], Ni(NH3)2(DNDZ)2 (1), Ni(CH3NH2)2(DNDZ)2 (2), Ni(C2H5NH2)2(DNDZ)2 (3) and Ni(C3H7NH2)2(DNDZ)2 (4), have been first synthesized and characterized. The crystal structures studies of 1 and 2 show that the central nickel(II) ion is six-coordinated by two O atoms and two N atoms from two DNDZ− anions and two N atoms from ammonias (methylamines) to form a distorted octahedral structure. Thermal decomposition processes of the four complexes were studied. The kinetic parameters of the exothermic decomposition process, specific heat capacities and adiabatic times-to-explosion for the four complexes were analyzed. All calculation and research results indicate that these complexes present relatively low thermal stability and easily decompose. Sensitivity tests reveal that the complexes are less sensitive to mechanical stimuli.

The search for new powerful energetic transition metal complexes based on 3,3'-dinitro-5,5'-bis-1,2,4-triazole-1,1'-diolate anion: a DFT study.

In this study, employing a new high oxygen balance energetic 3,3'-dinitro-5,5'-bis-1,2,4-triazole-1,1'-diolate anion (DNBTDO) as the bidentate ligand, NH3 and NH2NO2 as short energetic ligands, and Cu/Ni as the metal atoms, two series of novel energetic metal complexes were computationally designed. Their structures and properties were studied by density functional theory, electrostatic potential data, and molecular mechanics methods. The results showed that the designed metal complexes have high detonation performance and acceptable sensitivity: Cu/Ni(DNBTDO)(NH2NO2)2 (A3/B3) have better detonation properties and lower sensitivity than the most powerful CHNO explosive hexanitrohexaazaisowurtzitane, Cu/Ni(DNBTDO)(NH3)(NH2NO2) (A2/B2) have comparable energetic performance and sensitivity with 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, Ni(DNBTDO)(NH3)2 (B1) has comparative energy level and sensitivity with 1,3,5-trinitro-1,3,5-triazinane. These five energetic metal complexes may be attractive to energetic materials researchers. Besides, both the energetic ligands and metal atoms could have a great influence on the structures, heats of formation, detonation properties, and stability of energetic metal complexes, and the effects are coupled with each other. This study may be helpful in the search for and development of new improved energetic materials.

Synthesis, Crystal Structure, and Properties of Energetic Complexes Constructed from Transition Metal Cations (Fe, Co, Cu, and Pb) and BTO2−

Four transition metal energetic complexes with 5,5′‐bistetrazole‐1,1′‐diolatedehydrate (BTO) have been synthesized and structurally characterized by FT‐IR spectroscopy, elemental analysis, and single X‐ray diffraction. The thermal decomposition processes of the complexes and BTO were studied by means of the TG‐TDA technologies. The compatibility of the four complexes with RDX, HMX, NC, and Al powder was also investigated. Sensitivity tests reveal that the complexes are more insensitive to mechanical stimuli than RDX.

Di(1H-tetrazol-5-yl)methane as Neutral Ligand in Energetic Transition Metal Complexes.

The synthesis of di(1H-tetrazol-5-yl)methane (1, 5-DTM), starting from commercially available sodium azide and malononitrile, is described. This tetrazole was characterized and investigated for use as a neutral nitrogen-rich ligand in various energetic transition metal complexes: ([CuCl2(5-DTM)2]·2H2O (2), [Co(H2O)2(5-DTM)2]Cl2 (3), [Ni(H2O)2(5-DTM)2]Cl2 (4), [Co(H2O)2(5-DTM)2](NO3)2 (6), [Ni(H2O)2(5-DTM)2](NO3)2 (7), [Zn(H2O)2(5-DTM)2](NO3)2 (8), {[Cu3(SO4)2(5-DTM-H)2(H2O)4(5-DTM)2]·2H2O}∞ (9), [Cu(H2O)2(5-DTM)2](NO3)2 (11), [Cu(NO3)2(5-DTM)2]·2H2O (12), [Cu(NO3)2(5-DTM)2] (13), [Cu(H2O)2(5-DTM)2](ClO4)2 (14), and [Cu(ClO4)2(5-DTM)2] (15). Obtained coordination compounds were characterized using single crystal X-ray diffraction (except for 7 and 13), IR spectroscopy, elemental analysis, and differential thermal analysis. The sensitivities to external stimuli (impact, friction, electrostatic discharge) were determined. Complexes 12 and 13 were tested for their ignitability by laser irradiation.

Synthesis, Crystal Structure, and Properties of Energetic Copper(II) Complex based on 3,5-Dinitrobenzoic Acid and 1,5-Diaminotetrazole

Energetic copper(II) complexes based on 3,5-dinitrobenzoic acid (HDNBA) and 1,5-diaminotetrazole (DAT), Cu(DNBA)(2)(H2O)(2) (1) and Cu(DAT)(2)(DNBA)(2) (2) were synthesized and characterized by elemental analysis, IR spectroscopy, single-crystal and powder X-ray diffraction. In both complexes, Cu-II was coordinated to a plane tetragon, by four oxygen atoms from two DNBA(-) ions and two coordinated H2O molecules for 1, and by two oxygen atoms and two nitrogen atoms from different DNBA(-) ions and DAT ligands for 2. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were employed to measure the thermal decomposition processes and non-isothermal kinetics parameters of the complexes. The thermal decomposition onset temperatures of 1 and 2 are 321 and 177 degrees C. The apparent activation energies of the first exothermic decomposition peaks of 1 and 2 are 247.2 and 185.2 kJmol(-1). Both 1 (35 J, > 360 N) and 2 (12.5 J, > 360 N) are less sensitive than RDX. The catalytic effects on the decomposition of ammonium perchlorate (AP) of 1 and 2 were studied by DSC. All results supported the potential applications of the energetic complexes as additives of solid rocket propellants.

Catalytic reaction of ammonium perchlorate with energetic cobalt complex of 2,6-diamino-3,5-dinitropyrazine-1-oxide during thermal decomposition process

The purpose of this work was to study the catalytic reaction and its mechanism of ammonium perchlorate (AP) with cobalt complex of 2,6-diamino-3,5-dinitropyrazine-1-oxide (Co-LLM-105) during thermal decomposition process. At first, the catalytic performance of Co-LLM-105 on the thermal decomposition of AP was investigated by TG–DSC, TG-FTIR, non-isothermal kinetic and α–T kinetic curves analyses. Secondly, the thermal decomposition mechanism of Co-LLM-105 in the absence and presence of AP was proposed based on TG, DTG, DSC and thermolysis/RSFTIR analyses. The results showed that Co-LLM-105 exhibited excellent catalytic activity on the thermal decomposition of AP. Meanwhile, AP also exhibited some catalytic effects on the thermal decomposition of Co-LLM-105. Both of the components had catalytic effects on each other during the process. The formation of active CoCO3, Co3O4, CoO and Co(NH3)6(ClO4)2 in situ in the system accounted for the higher catalytic activity of Co-LLM-105 for the thermal decomposition of AP was deduced. Co-LLM-105 exhibited excellent catalytic activity on the thermal decomposition of AP. Meanwhile, AP also exhibited some catalytic effects on the thermal decomposition of Co-LLM-105. Both of the components had catalytic effects on each other during the process.

Three new energetic complexes with N,N-bis(1H-tetrazole-5-yl)-amine as high energy density materials: syntheses, structures, characterization and effects on the thermal decomposition of RDX.

Three new energetic complexes, [Pb(bta)(H2O)]n (1), [PbCu(bta)2(H2O)5]·2H2O (2) and PbCu(bta)2 (3) (H2bta = N,N-bis(1H-tetrazole-5-yl)-amine), have been synthesized and characterised. In particular, 3 was readily synthesized by dehydration of 2 at 190 °C. Single crystal X-ray diffraction revealed that 1 has a 3D framework structure and 2 presents a 3D supermolecular architecture. Thermoanalyses demonstrated that the main frames of 1 and 2 have good thermostabilities up to 314 °C for 1 and 231 °C for 2. Non-isothermal kinetic and thermodynamic parameters of exothermic decomposition processes of 1 and 2 were obtained by Kissinger's and Ozawa's methods. Based on the constant-volume combustion energies measured by a precise rotating-bomb calorimeter, the standard molar enthalpies of formation of 1 and 2 were determined. The calculation of the detonation properties of 1 and 2 and the impact sensitivity tests of 1, 2 and 3 were carried out. In addition, 1, 2 and 3 were explored as combustion promoters to accelerate the thermal decompositions of RDX (1,3,5-trinitro-1,3,5-triazine) by differential scanning calorimetry. Experimental results showed that 1, 2 and 3 can be used as HEDMs in the field of combustion promoters and insensitive 2 can be regarded as a safer form for mass storage and transportation than sensitive 3.

Axial substitution of a precursor resulted in two high-energy copper(ii) complexes with superior detonation performances.

The design and synthesis of explosives with high performance, good thermal stability, and low sensitivity is an important subject for the development of energetic materials. Energetic complexes have recently emerged as a promising energetic material form. As one of the representatives, [Cu(Htztr)2(H2O)2]n (H2tztr = 3-(1H-tetrazol-5-yl)-1H-triazole) was previously reported with good energetic performance, outstanding thermostability (Tdec = 345 °C) and low sensitivity to impact and friction stimuli. However, due to the existence of water molecules, its effective energy density is remarkably decreased, resulting in a diminished detonation performance. In order to further improve the detonation performance, using [Cu(Htztr)2(H2O)2]n as a precursor, {[Cu(Htztr)(H2O)]NO3}n (1) and [Cu(H2tztr)2(HCOO)2]n (2) were synthesized by the axial substitution reaction with NO3- and HCOO-. The structures of 1 and 2 were characterized by single crystal X-ray diffraction. Both of them exhibit high thermal stabilities and insensitivities to impact and friction. Moreover, the same DFT calculation methodology shows that the heat of detonation of 2 (3.5663 kcal g-1) is significantly higher than that of the precursor [Cu(Htztr)2(H2O)2]n (2.1281 kcal g-1). Meanwhile, the empirical Kamlet-Jacobs equations were used to theoretically predict the detonation properties of the title complexes, and the results show that 1 and 2 have excellent detonation velocity (D) and detonation pressure (P).

Coordination chemistry with 1-methyl-5H-tetrazole: cocrystallization, laser-ignition, lead-free primary explosives – one ligand, three goals

Numerous energetic coordination complexes (MnII, FeII, CoII, NiII, CuII, ZnII, and AgI) using 1-methyl-tetrazole as the ligand were synthesized and tuned by different counteranions (e.g. NO3−, ClO4−, picrate, and styphnate). They show great potential for mechanical or optical initiation systems.

ChemInform Abstract: A Biography of Potassium Complexes as Versatile, Green Energetic Materials

AbstractReview: 135 refs.

Two new complexes based on 2-(dinitromethylene)-1,3-diazacyclopentane (DNDZ): Synthesis, crystal structure and properties

Two new energetic complexes, Zn(NH3)2(DNDZ)2 and Cu(NH3)2(DNDZ)2 [DNDZ=2-(dinitromethylene)-1,3-diazacyclopentane], were first synthesized and structurally characterized. Zn(NH3)2(DNDZ)2 crystallizes in tetragonal crystal system with space group P4(1)2(1)2, but the crystal of Cu(NH3)2(DNDZ)2 is monoclinic with space group of C2/c. Zn2+ ion is coordinated by four N atoms from two NH3 molecules and two DNDZ− anions to form a distorted tetrahedron structure in Zn(NH3)2(DNDZ)2, while central Cu2+ ion coordinates with two O atoms and two N atoms from two DNDZ− anions and two N atoms of two NH3 molecules to form a six-coordinated octahedral structure in Cu(NH3)2(DNDZ)2. The thermal decomposition behaviors of the two complexes were studied with DSC and TG/DTG methods. Self-accelerating decomposition temperatures and critical temperatures are 164.7 and 166.4°C for Zn(NH3)2(DNDZ)2, and 149.6 and 150.8°C for Cu(NH3)2(DNDZ)2, respectively. The impact and friction sensitivities are >17.0J and 36% for Zn(NH3)2(DNDZ)2, and >10.0J and 56% for Cu(NH3)2(DNDZ)2, respectively. The two complexes exhibit lower sensitivity than analogous FOX-7 complexes.

Ca(II) and Ba(II) methyl carbazate energetic complexes: syntheses, crystal structures, and properties

New energetic materials, [Ca(MCZ)3(H2O)2](ClO4)2 and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}n, are synthesized and tried as alternatives to common primary explosives. Both the crystal structures were determined by single-crystal X-ray diffraction. The crystal of [Ca(MCZ)3(H2O)2](ClO4)2 belongs to the monoclinic, P21/c space group, a = 14.168(3) Å, b = 8.5938(18) Å, c = 18.889(4) Å, β = 111.234(2)°, V = 2143.8(8) Å3, ρ = 1.6893 g cm−3, and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}n belongs to the triclinic, P-1 space group, a = 7.166(2) Å, b = 10.461(2) Å, c = 11.738(4) Å, α = 110.563(5)°, β = 93.799(2)°, γ = 96.864(3)°, V = 812.4(4) Å3, ρ = 2.185 g cm−3. Their thermal stabilities were investigated by differential scanning calorimetry (DSC), and exothermic peak temperatures with a heating rate of 10 °C min−1 are 249.7 and 181.7 °C, respectively. Non-isothermal reaction kinetics parameters were calculated via both Kissinger’s method and Ozawa-Doyle’s method to work out EK = 124.6 kJ mol−1, lgAK = 10.38, EO = 126.7 kJ mol−1 for the calcium complex and EK = 100.3 kJ mol−1, lgAK = 9.50, EO = 102.6 kJ mol−1 for the barium complex. Additionally, the critical temperatures of thermal explosion, ΔS≠, ΔH≠, and ΔG≠ were calculated as −231.2 J K−1 mol−1, 120.417 kJ mol−1, 236.728 kJ mol−1 for the calcium complex and −230.6 J K−1 mol−1, 96.723 kJ mol−1, 195.938 kJ mol−1 for the barium complex. As for their explosive nature, sensitivities toward impact and friction were tested. Both [Ca(MCZ)3(H2O)2](ClO4)2 and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}n are insensitive to friction (>360 N); their impact sensitivities are acceptable (20 and 13 J). Both compounds are energetic complexes.

Synthesis and Properties of [Cd(HTRTR)2(H2O)4](HTNR)2 as an Energetic Complex

AbstractThe energetic complex, [Cd(HTRTR)2(H2O)4](HTNR)2 {HTRTR = 4‐[3‐(1,2,4‐triazol‐yl)‐1,2,4‐triaozle; HTNR– = styphnic acid anion) was synthesized and characterized by FT‐IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. It crystallizes triclinic in space group P$\bar{1}$ [a = 8.156(2) Å, b = 8.374(2) Å, c = 13.267(4) Å, α = 84.925(11)°, β = 87.016(11)°, γ = 63.683(5)°, V = 808.9(4) Å3, ρ = 1.940 g·cm–3]. The CdII ion is six‐coordinate with two HTRTRs and four water molecules. The thermal stabilities were investigated by differential scanning calorimetry (DSC). Non‐isothermal reaction kinetic parameters were calculated by Kissinger's and Ozawa‐Doyle's methods to obtain EK = 144.0 kJ·mol–1, lgAK = 14.22, and EO = 144.3 kJ·mol–1. The values of thermodynamic parameters, the peak temperature while β→0 (Tp0), free energy of activation (ΔG≠), entropy of activation (ΔS≠), and enthalpy of activation (ΔH≠) were obtained. Additionally, the enthalpy of formation was calculated by Hess's law on the basis of the experimental constant‐volume heat of combustion measured by bomb calorimetry, obtaining ΔfH°298 = 4985.5 kJ·mol–1. Finally, the sensitivities toward impact and friction were assessed according to relevant methods. The result indicates it as an insensitive energetic material.

Methyl carbazate energetic complexes: Transition metal perchlorates – Syntheses, crystal structures and properties

A series of transition metal (1 Mn(II), 2 Ni(II), 3 Cu(II), 4 Zn(II) and 5 Cd(II)) methyl carbazate perchlorate energetic complexes were synthesized in aqueous solution. The crystal structures were determined by single-crystal X-ray diffraction. The complex [Cu(MCZ)2](ClO4)2 belongs to the triclinic P1¯ space group. The Mn(II), Ni(II), Zn(II) and Cd(II) complexes all are monoclinic, P21/c space group. Their thermal stabilities were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All the compounds show good thermal stabilities (1, 2, 4 and 5 under 200°C; 3 under 160°C). Non-isothermal reaction kinetics parameters, the critical temperatures of thermal explosion, ΔS≠, ΔH≠ and ΔG≠ were calculated. Their impact and friction sensitivities were tested, and their sensitivity levels are acceptable. The coordinated perchlorates reduce the thermal stability, but improve the decomposition rate immensely as well as the sensitivities.

Synthesis and Characterization of Tetrahedral Zinc(II) Complexes with 3, 6,7‐Triamino‐7H‐[1, 2,4]triazolo[4, 3‐b][1, 2,4]triazole as Nitrogen‐Rich Ligand

AbstractTriaminotriazolotriazole (TATOT) was used as a nitrogen‐rich ligand for the formation of the energetic ZnII complexes [ZnCl2(TATOT)2]·H2O (2), [Zn(H2O)(TATOT)3](NO3)2·2H2O (3), and [Zn(TATOT)4](ClO4)2·2H2O (4). The zinc species were prepared in a straightforward and inexpensive synthesis. The complexes 2–4 were structurally characterized using X‐ray diffraction. Additionally, the compounds were characterized using elemental analysis and infrared (IR) spectroscopy. Finally, the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA) and BAM (Bundesanstalt für Materialforschung und ‐prüfung) methods.

Two energetic complexes incorporating 3,5-dinitrobenzoic acid and azole ligands: microwave-assisted synthesis, favorable detonation properties, insensitivity and effects on the thermal decomposition of RDX

The two energetic complexes reported may act as attractive candidates for green propellants.

Synthesis and Characterization of Four Energetic Transition Metal Complexes of 3,4-Diamino-1,2,4-triazole

Synthesis and Characterization of Four Energetic Transition Metal Complexes of 3,4-Diamino-1,2,4-triazole